U.S. patent application number 15/328009 was filed with the patent office on 2017-05-25 for light guide plate display device.
The applicant listed for this patent is Panasonic Intellectual Property Management Co., Ltd.. Invention is credited to ATSUSHI FUKUI, KEIZOU MATSUMURA, TAKAYUKI YAMAGUCHI.
Application Number | 20170146721 15/328009 |
Document ID | / |
Family ID | 55439320 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170146721 |
Kind Code |
A1 |
FUKUI; ATSUSHI ; et
al. |
May 25, 2017 |
LIGHT GUIDE PLATE DISPLAY DEVICE
Abstract
A light guide plate display device includes a light guide plate,
a plurality of light source devices, and a plurality of prisms. The
light guide plate includes a display face and a plurality of end
faces, and is formed of a light transmitting material. The light
source devices are provided along respective end faces of the light
guide plate, and radiate light from the end face toward an inside
of the light guide plate. The prisms are formed inside the light
guide plate. The prisms respectively have a plurality of side faces
which face the respective light source devices. The respective side
faces are inclined at least in two stages of a transmitting
inclined face which transmits light radiated from the light source
device, and a reflecting inclined face which reflects the light
radiated from the light source device, and outputs the light to the
display face, in a thickness direction of the light guide
plate.
Inventors: |
FUKUI; ATSUSHI; (Osaka,
JP) ; MATSUMURA; KEIZOU; (Osaka, JP) ;
YAMAGUCHI; TAKAYUKI; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Intellectual Property Management Co., Ltd. |
Osaka |
|
JP |
|
|
Family ID: |
55439320 |
Appl. No.: |
15/328009 |
Filed: |
June 2, 2015 |
PCT Filed: |
June 2, 2015 |
PCT NO: |
PCT/JP2015/002770 |
371 Date: |
January 20, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/0031 20130101;
G02B 6/0058 20130101; G02B 6/002 20130101; G02B 6/0088 20130101;
G02B 6/0043 20130101; G02B 6/006 20130101; G09F 13/16 20130101;
G09F 13/14 20130101; G02B 6/0036 20130101; G02B 6/003 20130101;
G02B 6/0068 20130101; G09F 13/18 20130101; G02B 6/0083
20130101 |
International
Class: |
F21V 8/00 20060101
F21V008/00; G09F 13/16 20060101 G09F013/16 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 2014 |
JP |
2014-178613 |
Claims
1. A light guide plate display device comprising: a light guide
plate which includes a display face and a plurality of end faces,
and is formed of a light transmitting material; a plurality of
light source devices which are provided along the plurality of end
faces of the light guide plate, respectively, and radiate light
from the respective plurality of end faces of the light guide plate
toward an inside of the light guide plate; and a plurality of
prisms which are formed inside the light guide plate, wherein the
respective plurality of prisms have a plurality of side faces which
face the respective plurality of light source devices, and wherein
the respective plurality of side faces are inclined in at least two
stages of a transmitting inclined face which transmits light
radiated from the respective plurality of light source devices, and
a reflecting inclined face which reflects the light radiated from
the respective plurality of light source devices, and outputs the
light to the display face, in a thickness direction which is
perpendicular to the display face of the light guide plate.
2. The light guide plate display device of claim 1, wherein the
light guide plate has a rear face on a side opposite to the display
face, and wherein the transmitting inclined face of the respective
plurality of prisms is connected to the rear face.
3. The light guide plate display device of claim 1, wherein the
reflecting inclined face of the respective plurality of prisms is
configured of a first reflecting inclined face and a second
reflecting inclined face of which inclination angles are different
from each other, and wherein the side faces of the respective
plurality of prisms are respectively inclined in three stages of
the first reflecting inclined face, the second reflecting inclined
face, and the transmitting inclined face in the thickness direction
of the light guide plate.
4. The light guide plate display device of claim 1, wherein the
respective plurality of prisms further include a planar face which
connects the plurality of side faces to each other in the inside of
the light guide plate.
5. The light guide plate display device of claim 1, further
comprising: a dummy prism which includes a plurality of side faces
which face the plurality of light source devices, wherein the
plurality of side faces of the dummy prism are configured of a
transmitting inclined face which transmits light radiated from the
respective plurality of light source devices.
6. The light guide plate display device of claim 5, wherein an area
of a region in which the plurality of prisms and the dummy prism
are formed is one tenth or less of an area of a region in which
neither the plurality of prisms nor the dummy prism is formed.
7. The light guide plate display device of claim 1, wherein the
plurality of light source devices respectively include a plurality
of light sources which are arranged along one of the plurality of
end faces of the light guide plate, and include an effective output
face which faces the one of the plurality of end faces of the light
guide plate, a light source board which includes a light source
mounting face on which the plurality of light sources are mounted,
a light input lens which is disposed between the plurality of light
sources and the one of the plurality of end faces of the light
guide plate, and a reflecting plate which surrounds the plurality
of light sources, the light source board, and the light input lens
except for a portion between the light source board and the one of
the plurality of end faces of the light guide plate, wherein the
light input lens includes a first lens face which faces the
plurality of light sources, and makes light radiated from the
respective plurality of light sources parallel, and a second lens
face which faces the one of the plurality of end faces of the light
guide plate, and diffuses the light which is paralleled on the
first lens face, wherein the reflecting plate includes a neck
portion in which an interval of the light guide plate in the
thickness direction becomes extremely small, between the effective
output face and the light source mounting face, and the reflecting
plate is open so as to expand from the neck portion toward the one
of the plurality of end faces of the light guide plate, and wherein
an interval of the reflecting plate in the neck portion is larger
than a width of the effective output face, in the thickness
direction of the light guide plate.
8. The light guide plate display device of claim 7, wherein the
reflecting plate is a mirror-finished reflecting plate.
9. The light guide plate display device of claim 7, wherein the
light source mounting face of the light source board is a black
color.
10. The light guide plate display device of claim 7, wherein the
respective plurality of end faces of the light guide plate are
formed in a protruded V shape toward the respective plurality of
light source devices.
Description
TECHNICAL FIELD
[0001] The present invention relates to a light guide plate display
device which displays a pattern such as characters or drawing
patterns using a light guide plate.
BACKGROUND ART
[0002] For example, a light guide plate display device in the
related art which is disclosed in PTL 1 includes a light guide
plate and a trigonal prismatic prism. Light radiated from an end
face to an inside of the light guide plate is output from a display
face of the light guide plate in the prism. In this manner, the
light guide plate display device displays a pattern. FIGS. 25 and
26 are diagrams which illustrate the light guide plate display
device in the related art which is described in PTL 1.
[0003] The light guide plate display device described in PTL 1
includes light guide plate 12, four light source device groups 211a
to 211d, 212a to 212d, 213a to 213d, and 214a to 214d which radiate
light from different directions, respectively, toward end faces of
light guide plate 12, and four prism groups 19a, 19b, 19c, and 19d.
In FIG. 25, as prism groups 19a, 19b, 19c, and 19d, each one prism
is illustrated, respectively; however, in practice, prism groups
are formed by being provided with a plurality of prisms in the
inside of light guide plate 12.
[0004] Prism group 19a is formed in a trigonal prismatic shape with
inclined faces which incline to light guide plate 12, respectively,
and a perpendicular face which is perpendicular to light guide
plate 12, and the inclined face of prism group 19a is provided so
as to face a radiation direction of light sources 211a to 211d.
Light input to the inclined face of prism group 19a is reflected in
a display direction of light guide plate 12, and is visually
recognized by an observer. On the other hand, since light input to
the perpendicular face of prism group 19a penetrates the prism, the
light is not visually recognized by an observer. Prism group 19a is
disposed at an appropriate position in light guide plate 12, and
pattern P21 is displayed when light sources 211a to 211d are turned
on.
[0005] Inclined faces of prism group 19b are provided so as to face
radiation directions of light source devices 212a to 212d, inclined
faces of prism group 19c are provided so as to face radiation
directions of light source devices 213a to 213d, and inclined faces
of prism group 19d are provided so as to face radiation directions
of light source devices 214a to 214d. In this manner, the inclined
faces of prism group 19b reflect light radiated from light source
devices 212a to 212d, and pattern P22 is displayed, the inclined
faces of prism group 19c reflect light radiated from light source
devices 213a to 213d, and pattern P23 is displayed, and the
inclined faces of prism group 19d reflect light radiated from light
source devices 214a to 214d, and pattern P24 is displayed. As
described above, by performing switching of ON or OFF of light
source devices 211a to 211d, 212a to 212d, 213a to 213d, and 214a
to 214d, it is possible to display patterns P21 to P24 of four
types, and a combination thereof on light guide plate 12.
CITATION LIST
Patent Literature
[0006] PTL 1: Japanese Patent Unexamined Publication No.
2006-75362
SUMMARY OF THE INVENTION
[0007] The present invention provides a light guide plate display
device which can display a plurality of patterns, and improve
transparency of a light guide plate.
[0008] A light guide plate display device in the present invention
includes a light guide plate, a plurality of light source devices,
and a plurality of prisms. The light guide plate includes a display
face and a plurality of end faces, and is formed of a light
transmitting material. The light source devices are provided along
respective end faces of the light guide plate, and radiate light
from the end face toward an inside of the light guide plate. The
prisms are formed inside the light guide plate. The prisms
respectively have a plurality of side faces which face the
respective light source devices. The side faces are respectively
inclined at least in two stages of a transmitting inclined face
which transmits light radiated from the light source device, and a
reflecting inclined face which reflects the light radiated from the
light source device, and outputs the light to the display face in a
thickness direction of the light guide plate.
[0009] It is possible to display a plurality of patterns in one
prism group, using the above described prism. Therefore, it is not
necessary to use prism groups of the same number as those of the
light source device. In addition, it is possible to set a total
area of a region in which prisms are formed with respect to an area
of the display face of the light guide plate to be small, and
improve transparency of the light guide plate.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1 is a plan view of a light guide plate display device
according to an embodiment of the present invention.
[0011] FIG. 2 is a sectional view which is cut in line 2-2 of the
light guide plate display device illustrated in FIG. 1.
[0012] FIG. 3 is a plan view and a side view of a prism according
to the embodiment of the present invention.
[0013] FIG. 4 is a diagram which illustrates an operation of a
prism illustrated in FIG. 3.
[0014] FIG. 5 is a diagram which exemplifies a state in which a
pattern is displayed in the light guide plate display device
illustrated in FIG. 1.
[0015] FIG. 6 is a diagram which exemplifies another state in which
a pattern is displayed in the light guide plate display device
illustrated in FIG. 1.
[0016] FIG. 7 is a diagram which exemplifies still another state in
which a pattern is displayed in the light guide plate display
device illustrated in FIG. 1.
[0017] FIG. 8 is a diagram which exemplifies still further another
state in which a pattern is displayed in the light guide plate
display device illustrated in FIG. 1.
[0018] FIG. 9 is a diagram which exemplifies still further another
state in which a pattern is displayed in the light guide plate
display device illustrated in FIG. 1.
[0019] FIG. 10 is a diagram which illustrates an operation of
another prism according to the embodiment of the present
invention.
[0020] FIG. 11 is a plan view and a side view of a dummy prism
according to the embodiment of the present invention.
[0021] FIG. 12 is a diagram which illustrates an operation of the
dummy prism illustrated in FIG. 11.
[0022] FIG. 13 is a diagram which exemplifies a disposal example of
the prism according to the embodiment of the present invention.
[0023] FIG. 14 is a diagram which illustrates another disposal
example of the prism according to the embodiment of the present
invention.
[0024] FIG. 15 is a diagram which illustrates still another
disposal example of the prism according to the embodiment of the
present invention.
[0025] FIG. 16 is a diagram which illustrates still further another
disposal example of the prism according to the embodiment of the
present invention.
[0026] FIG. 17 is a partial sectional view of the light source
device and the light guide plate according to the embodiment of the
present invention.
[0027] FIG. 18 is a partial sectional view of the light source
device and the light guide plate illustrated in FIG. 17.
[0028] FIG. 19 is a diagram which illustrates an operation of the
light source device illustrated in FIG. 17.
[0029] FIG. 20 is a diagram which illustrates another operation of
the light source device illustrated in FIG. 17.
[0030] FIG. 21 is a diagram which illustrates an operation of the
light source device illustrated in FIG. 18.
[0031] FIG. 22 is a partial sectional view of a light source device
and a light guide plate according to another embodiment of the
present invention.
[0032] FIG. 23 is a plan view of a light guide plate display device
according to still another embodiment of the present invention.
[0033] FIG. 24 is a partial sectional view of a light source device
and a light guide plate according to still further another
embodiment of the present invention.
[0034] FIG. 25 is a diagram which illustrates a display pattern and
a prism of a light guide plate display device in the related
art.
[0035] FIG. 26 is a diagram which illustrates a display pattern and
a light source device of the light guide plate display device
illustrated in FIG. 25.
[0036] FIG. 27 is a plan view and a sectional view of another light
guide plate display device in the related art.
DESCRIPTION OF EMBODIMENT
[0037] Problems in a light guide plate display device in the
related art will be simply described in advance of descriptions of
an embodiment of the present invention. In the configuration
described in PTL 1, it is possible to display only one pattern with
respect to one prism group. Therefore, in order to display patterns
of four types, it is necessary to perform disposing, using four
prism groups 19a to 19d with different directions of inclined
faces, respectively, in light guide plate 12. Therefore, a total
area of a region in which prisms are formed becomes large with
respect to an area of a display face of light guide plate 12. As a
result, transparency of light guide plate 12 deteriorates.
[0038] FIG. 27 is a diagram which illustrates a light guide plate
display device in another related art in which a quadrangular
pyramid-shaped prism is used. Each inclined face of quadrangular
pyramid-shaped prism 32 is formed in the same shape, and it is
possible to display a single pattern with uniform brightness, using
light from any direction. According to the configuration, it is
possible to display only one pattern, since quadrangular
pyramid-shaped prism 32 with a simple structure is used.
[0039] Hereinafter, light guide plate display device 10 according
to an embodiment of the present invention will be described with
reference to drawings. FIG. 1 is a plan view of light guide plate
display device 10, and FIG. 2 is a sectional view of light guide
plate display device 10 which is cut along line 2-2. FIG. 3 is a
plan view and a side view of prism 102 of light guide plate display
device 10. Light guide plate display device 10 includes light
source device 100, light guide plate 101, and plurality of prisms
102.
[0040] Light guide plate 101 is a planar plate-shaped material
including display face 121, rear face 120, and plurality of end
faces 119, and is formed of a material with transparency such as
polycarbonate and acryl, for example. For example, specifically,
light guide plate 101 is formed in a quadrangular shape when
planarly viewed, and includes four end faces 119.
[0041] Four light source devices 100 are provided along four end
faces 119 of light guide plate 101, and radiate light from end
faces 119 of light guide plate 101 toward an inside of light guide
plate 101. Prisms 102 are formed inside light guide plate 101.
Prisms 102 may be formed of a light transmitting material with a
low refractive index compared to a material of light guide plate
101, respectively, and may be intervals provided inside light guide
plate 101.
[0042] As illustrated in FIG. 3, respective prisms 102 are formed
in a rectangular shape when viewed planarly, and include four side
faces 102A which face light source device 100, respectively. Side
faces 102A are inclined in two stages of reflecting inclined face
.alpha. and transmitting inclined face .beta., in a thickness
direction of light guide plate 101. An angle formed by transmitting
inclined face .beta. and rear face 120, that is, inclination angle
.theta..sub..beta. of transmitting inclined face .beta. is
approximately 90.degree.. An angle formed by reflecting inclined
face .alpha. and line L which is parallel to rear face 120, that
is, inclination angle .theta..sub..alpha. of reflecting inclined
face .alpha. is smaller than inclination angle .theta..sub..beta.,
and for example, 46.degree. to 52.degree..
[0043] That is, light guide plate display device 10 includes light
guide plate 101, light source device 100, and plurality of prisms
102. Light guide plate 101 includes display face 121 and plurality
of end faces 119, and is formed of a light transmitting material.
Plurality of light source devices 100 are provided along plurality
of end faces 119 of light guide plate 101, respectively, and are
disposed so as to radiate light from respective end faces 119
toward the inside of light guide plate 101. Plurality of prisms 102
are formed inside light guide plate 101. Respective prisms 102
include plurality of side faces 102A which face respective light
source devices 100. Respective side faces 102A are inclined in at
least two stages of transmitting inclined face .beta. which
transmits light which is radiated from light source device 100, and
reflecting inclined face a which outputs the light radiated from
light source device 100 to display face 121 by reflecting the
light, in the thickness direction of light guide plate 101. In this
manner, side face 102A includes transmitting inclined face .beta.
and reflecting inclined face .alpha. with an inclination different
from that of transmitting inclined face .beta., in the thickness
direction of light guide plate 101. The thickness direction of
light guide plate 101 is a direction perpendicular to display face
121.
[0044] Subsequently, an operation of light guide plate display
device 10 will be described with reference to FIG. 4. Light beams
133 to 136 are radiated from light source device 100 in FIG. 1.
Light beam 133 is inclined so as to face rear face 120 of light
guide plate 101 in the inside of light guide plate 101, and is
input to transmitting inclined face .beta. of prism 102. Since
inclination angle .theta..sub..beta. of transmitting inclined face
.beta. is approximately 90.degree., most of light beams 133
transmit transmitting inclined face .beta. of prism 102.
Thereafter, light beam 133 is output from rear face 120 of light
guide plate 101.
[0045] Light beam 134 is inclined so as to face display face 121 of
light guide plate 101 in the inside of light guide plate 101, and
is input to transmitting inclined face .beta. of prism 102.
Thereafter, most of light beams 134 penetrate transmitting inclined
face .beta., penetrate reflecting inclined face .alpha. or
transmitting inclined face .beta. on a side opposite to prism 102,
and return to the inside of light guide plate 101 again.
[0046] Light beam 135 is inclined so as to face rear face 120 of
light guide plate 101 in the inside of light guide plate 101, and
is input to reflecting inclined face .alpha. of prism 102.
Thereafter, most of light beams 135 penetrate reflecting inclined
face .alpha., and return to light guide plate 101 again. Since
light beams 133 to 135 are not output from display face 121 of
light guide plate 101, the light beams do not contribute to a
pattern display.
[0047] Light beam 136 is inclined so as to face display face 121 of
light guide plate 101 in the inside of light guide plate 101, and
is input to reflecting inclined face .alpha. of prism 102.
Thereafter, most of light beams 136 are totally reflected on
reflecting inclined face .alpha., and are output from display face
121 of light guide plate 101. Light output from display face 121 is
recognized by an observer. Therefore, light beam 136 contributes to
a pattern display of light guide plate display device 10. That is,
among light beams 133 to 136, only light beam 136 contributes to a
pattern display. In respective prisms 102, when an area of
reflecting inclined face .alpha. becomes large with respect to an
area of transmitting inclined face .beta., a ratio of light beam
136 contributing to a pattern display increases. Therefore,
luminance in a pattern display is proportional to the area of
reflecting inclined face .alpha..
[0048] In light guide plate display device 10, side face 102A of
prism 102 faces light source device 100. Side face 102A can display
a plurality of patterns in one prism group by being inclined in two
stages of reflecting inclined face .alpha. and transmitting
inclined face .beta.. Hereinafter, descriptions will be made in
detail.
[0049] FIG. 5 illustrates patterns A, B, C, and D which are
displayed by light source devices 100a, 100b, 100c, and 100d. FIG.
6 illustrates a state in which only light source device 100a is
turned on, and only pattern A is displayed on the display face of
light guide plate 101. In prism 102 which is located at a portion
of pattern A, an area of reflecting inclined face .alpha. on the
side face which faces light source device 100a each other is set to
be large. Therefore, light radiated from light source device 100a
is easily output to the display face by being reflected on
reflecting inclined face .alpha. of prism 102 which is located at a
portion of pattern A. As a result, only luminance of the portion of
pattern A is improved. On the other hand, at a portion other than
pattern A, the area of reflecting inclined face .alpha. on the side
face which faces light source device 100a each other is set to be
small, in prism 102. Therefore, luminance at the portion other than
pattern A decreases. In this manner, it is possible to display
pattern A by turning on light source device 100a.
[0050] FIG. 7 illustrates a state in which only light source device
100b is turned on, and only pattern B is displayed on the display
face of light guide plate 101. FIG. 8 illustrates a state in which
only light source device 100c is turned on, and only pattern C is
displayed on the display face of light guide plate 101. Similarly,
FIG. 9 illustrates a state in which only light source device 100d
is turned on, and only pattern D is displayed on the display face
of light guide plate 101. A method of displaying patterns B, C, and
D is the same as a display method of pattern A. That is, in prism
102 in pattern portions, an area of reflecting inclined face
.alpha. on a face which faces a corresponding light source device
each other among light source devices 100b to 100d is set to be
large. Patterns A, B, C, and D can be displayed independently;
however, a plurality of patters may be displayed in an overlapping
manner. For example, when light source device 100a and light source
device 100c are turned on at the same time, pattern A and pattern C
are displayed by being overlapped.
[0051] As described above, in light guide plate display device 10,
it is possible to display a plurality of patterns using one prism
group, when the side face which faces the light source device of
prism 102 each other is inclined in two stages of reflecting
inclined face .alpha. and transmitting inclined face .beta..
Therefore, in the light guide plate display device which displays a
plurality of patterns, it is not necessary to use the same number
of prism groups as that of the light source device. It is possible
to make a total area of a region in which prisms are formed small
with respect to an area of the display face of the light guide
plate, and improve transparency of light guide plate 101.
[0052] It is preferable that transmitting inclined face .beta. of
prism 102 be connected to rear face 120. For example, a mold for
forming prism 102 has a shape in which a shape of prism 102 is
remained, and the shape is formed, using a cutting tool for
machining a mold. In this case, an inclined face of prism 102 is
formed, using a blade edge of the cutting tool. However, it is not
easy to obtain a complete angle depending on a blade edge of the
cutting tool, and a minute curved face portion occurs at an
intersection portion of rear face 120 of light guide plate 101 and
inclined face of prism 102.
[0053] By causing light in the inside of light guide plate 101 to
be totally reflected, and changing an angle thereof, reflecting
inclined face .alpha. outputs the light to display face 121 side.
In this manner, since total reflection of reflecting inclined face
.alpha. is used, a difference in change in angle of input light
remarkably influences on luminance in displaying of patterns. A
change in angle of reflected light becomes twice of a change in
angle input to an inclined face of prism 102. For example, when a
refractive index of light guide plate 101 is 1.59, a change in
angle of output light when a light beam is output into the air from
light guide plate 101 becomes 2.times.1.59=3.18 times of a change
in angle input to the inclined face of prism 102.
[0054] When it is assumed that reflecting inclined face .alpha. is
in direct contact with rear face 120 of light guide plate 101, a
minute curved face occurs at an intersection portion of rear face
120 and reflecting inclined face .alpha.. When a light beam is
totally reflected at the curved face portion, an orientation of a
light beam output from light guide plate 101 to the display face is
remarkably changed, and it causes a decrease in display luminance,
and stray light. On the other hand, when transmitting inclined face
.beta. of prism 102 is connected to rear face 120, even when a
minute curved face portion occurs at an intersection portion of
rear face 120 and transmitting inclined face .beta., light is not
output from transmitting inclined face .beta. in a direction of
display face 121 of light guide plate 101. Therefore, there is no
case in which the curved face portion remarkably influences on a
pattern display. As described above, when transmitting inclined
face .beta. of prism 102 is connected to rear face 120, it is
possible to prevent a decrease in display luminance, or stray light
when displaying patterns.
[0055] Here, it is preferable to set an area of reflecting inclined
face .alpha. of prism 102 located at a position far from light
source device 100 to be larger than an area of reflecting inclined
face .alpha. of prism 102 located at a position close to light
source device 100. Hereinafter, descriptions will be made in
detail.
[0056] Luminance in a pattern display is not only proportional to
an area of reflecting inclined face .alpha., but also proportional
to density of light which reaches prism 102. Light with high
density in light guide plate 101 reaches prism 102 located at a
position close to light source device 100. On the other hand, since
light reaches after penetrating many other prisms 102, light with
low density in light guide plate 101 is input to prism 102 located
at a position far from light source device 100. Therefore, it is
possible to make luminance in a pattern display to be balanced, by
setting an area of reflecting inclined face .alpha. of prism 102
located at a position far from light source device 100 to be larger
than an area of reflecting inclined face .alpha. of prism 102
located at a position close to light source device 100.
[0057] As illustrated in FIG. 10, it is preferable that the
reflecting inclined face of prism 102 be configured of first
reflecting inclined face .alpha.1 and second reflecting inclined
face .alpha.2. FIG. 10 is a diagram which illustrates an operation
of another prism 102 according to the embodiment of the present
invention. A side face which faces the light source device of prism
102 is inclined in three stages of first reflecting inclined face
.alpha.1, second reflecting inclined face .alpha.2, and
transmitting inclined face .beta. in the thickness direction of
light guide plate 101. Auxiliary lines L1 and L2 in FIG. 10 are
parallel to rear face 120, and an angle formed by auxiliary line L1
and first reflecting inclined face .alpha.1, that is, an angle
formed by inclination angle .theta..sub..alpha.1 of first
reflecting inclined face .alpha.1, and an angle formed by auxiliary
line L2 and second reflecting inclined face .alpha.2, that is,
inclination angle .theta..sub.a2 of second reflecting inclined face
.alpha.2 are slightly different. For example, .theta..sub..alpha.1
is 51.degree., and .theta..sub..alpha.2 is 47.degree..
[0058] In FIG. 10, light beams 137 and 138 are parallel to each
other. Light beam 137 is inclined toward display face 121 in the
inside of light guide plate 101, and is input to second reflecting
inclined face .alpha.2 of prism 102. Thereafter, light beam 137 is
totally reflected on second reflecting inclined face .alpha.2, and
is output from display face 121 of light guide plate 101. On the
other hand, light beam 138 is input to first reflecting inclined
face .alpha.1 of prism 102, in a state of being inclined toward
display face 121 in the inside of light guide plate 101.
Thereafter, light beam 138 is totally reflected on first reflecting
inclined face .alpha.1, and is output from display face 121.
[0059] .theta..sub..alpha.1 and .theta..sub..alpha.2 are angles
which are different from each other. Therefore, light beams 137 and
138 which are parallel to each other before being totally reflected
are not parallel after being reflected on second reflecting
inclined face .alpha.2 and first reflecting inclined face .alpha.1,
respectively, and are reflected in different directions by
.phi.1=2|.theta..sub..alpha.1-.theta..sub..alpha.2|. When a
refractive index of light guide plate 101 is set to n, light beams
137 and 138 which are output from display face 121 of light guide
plate 101 are output in different directions by an angle of
.phi.2=2n|.theta..sub..alpha.1-.theta..sub..alpha.2|. That is, when
the reflecting inclined face is configured of first reflecting
inclined face .alpha.1 and second reflecting inclined face
.alpha.2, it is possible to output light in different directions
depending on whether the light is input to first reflecting
inclined face .alpha.1 or to second reflecting inclined face
.alpha.2, even when the light is input from the same direction. In
this manner, it is possible to expand a viewing angle in a pattern
display.
[0060] It is preferable that light guide plate display device 10
include dummy prism 103 which is illustrated in FIG. 11, at a
pattern non-display portion of light guide plate 101. FIG. 11 is a
plan view and a side view of dummy prism 103.
[0061] A side face which faces light source device 100 each other
is configured of transmitting inclined face .beta. in dummy prism
103. Therefore, as illustrated in FIG. 12, dummy prism 103 does not
output light toward display face 121 even when the light beam is
input from any direction. Accordingly, dummy prism 103 does not
contribute to a pattern display.
[0062] In a case in which dummy prism 103 is not provided at a
non-display portion of patterns, prism 102 is provided only at a
pattern display portion, and the prism is not provided at the
non-display portion of patterns, when light guide plate 101 is
observed from display face 121 at a time of turning off light
source device 100, a difference occurs in appearance between the
pattern display portion and the non-display portion of patterns,
though it is slight. Therefore, the pattern display portion is
recognized by an observer, and a display quality of patterns
deteriorates, even when light source device 100 is turned off.
[0063] On the other hand, if dummy prism 103 is provided in the
non-display portion of patterns, when light guide plate 101 is
observed from display face 121, the light guide plate is crowded
with dummy prism 103 and prism 102. Therefore, there is a small
difference in appearance between the pattern display portion and
the non-display portion of patterns when light source device 100 is
turned off. In this manner, it is not easy for an observer to
recognize the pattern display portion when light source device 100
is turned off, and it is possible to improve a display quality of
patterns, eventually.
[0064] In a case in which a total area of a region in which prism
102 is formed is extremely small with respect to an area of display
face 121 of light guide plate 101, the difference in appearance
between the pattern display portion and the non-display portion of
patterns is small. Therefore, dummy prism 103 may not be
provided.
[0065] It is preferable that planar face .gamma. which connects
each side face to each other be provided inside light guide plate
101 in prism 102. In a case in which planar face .gamma. is not
provided in prism 102, most of light which penetrates display face
121 from rear face 120 becomes light which passes through a region
in which prism 102 is not provided, and light which passes through
reflecting inclined face .alpha. of prism 102. Since reflecting
inclined face .alpha. is inclined to light guide plate 101 when an
observer sees through light guide plate 101, light passes through
the region in which prism 102 is not provided, and light which
passes through reflecting inclined face .alpha. is remarkably
different in appearance. Therefore, a presence of prism 102 becomes
conspicuous.
[0066] When planar face .gamma. is provided in prism 102, most of
light which penetrates display face 121 from rear face 120 becomes
light which passes through the region in which prism 102 is not
provided, and light which passes through planar face .gamma.. Since
there is a small difference in appearance between light which
passes through the region in which prism 102 is not provided and
the light which passes through planar face .gamma., it is possible
to make the presence of prism 102 inconspicuous. It is possible to
make the presence of prism 102 more inconspicuous, by setting an
area of planar face .gamma. large with respect to reflecting
inclined face .alpha.. In a case in which dummy prism 103 is
provided, the planar face may be provided also in the dummy
prism.
[0067] In the inside of light guide plate 101, it is preferable to
set an area of the region (forming area) in which prism 102 and
dummy prism 103 are provided to be smaller than an area of a region
(non-forming region) in which both of prism 102 and dummy prism 103
are not provided. Specifically, it is preferable to set an area of
the forming region to be one tenth or less of the area of the
non-forming region. In this case, it is not easy for an observer to
recognize prism 102 and dummy prism 103, and transparency of light
guide plate 101 improves at a time of turning off light source
device 100.
[0068] When setting a length of one side of the base of prism 102
and dummy prism 103 to q, and an approximate pitch of prism 102 and
dummy prism 103 to p, it is preferable to set q<p/sqrt (10).
Here, sqrt denotes a square root.
[0069] In order to perform a pattern display, it is necessary to
cause light in the inside of light guide plate 101 to be totally
reflected on reflecting inclined face .alpha. of prism 102, and to
be output from display face 121 of light guide plate 101. In order
to do that, as illustrated in FIG. 4, it is necessary to secure
reflecting position 140 at which light beam 136 is reflected on
rear face 120 of light guide plate 101 before being input to
reflecting inclined face .alpha. of prism 102. For example, when
prism 102 is densely disposed too much, there is a case in which
reflecting position 140 is overlapped with adjacent prism 102. In
this case, prisms 102 which are adjacent to each other have an
influence on light beam 136, and luminance of output light for a
pattern display decreases. Accordingly, it is possible to secure
reflecting position 140 when sufficient intervals between prisms
102 can be obtained, and maintain luminance of output light for
performing pattern display without being influenced by a light beam
each other between prisms 102. In this case, the area of the
forming region of the prism and dummy prism 103 becomes one tenth
or less of the non-forming region, as described above. Therefore,
it is not easy for an observer to recognize prism 102 and dummy
prism 103, and transparency of light guide plate 101 improves.
[0070] Disposal examples of prism 102 and dummy prism 103 are
illustrated in FIGS. 13 to 16. In FIG. 13, prism 102 and dummy
prism 103 are disposed at equal intervals. In FIG. 14, prism 102
and dummy prism 103 are disposed in six directions, and are
disposed at equal intervals therebetween.
[0071] In FIG. 15, prism 102 and dummy prism 103 are disposed at
random. Specifically, disposals of prism 102 and dummy prism 103
are set, using a uniform random number in which a predetermined
initial value is used. In FIG. 16, prism 102 and dummy prism 103
are disposed at different pitches depending on a location. That is,
a pitch in the vicinity of a center of light guide plate 101 is
rough, and the pitch becomes fine when getting closer to light
source device 100.
[0072] In a case in which plurality of light guide plate display
devices 10 are used by being overlapped, the number of patterns
which can be displayed increases; however, there is a concern that
moire may occur between plurality of light guide plate display
devices 10. Therefore, it is possible to suppress an occurrence of
moire by changing a pitch of prism 102, in each light guide plate
display device.
[0073] Accordingly, in a case in which prism 102 and dummy prism
103 are randomly disposed as illustrated in FIG. 15, positions of
prism 102 and dummy prism 103 are set, using a uniform random
number in which a predetermined initial value is used in each of
the light guide plates. That is, each of the light guide plates is
differently disposed. Alternatively, it may be a configuration in
which two-dimensional disposal is performed, using super uniform
distribution which is referred to as Halton sequence or Faure
sequence, a prism position is set, using a different cardinal
number which is different in each light guide plate which is used
by being at least overlapped, and different disposal is performed
in each light guide plate. As illustrated in FIG. 16, in a case in
which prism 102 and dummy prism 103 are disposed at different
pitches depending on locations, and two light guide plates are
overlapped, disposal is performed so that changing directions of
pitches are opposite to each other.
[0074] It is preferable to set the disposal pitch of prism 102 and
dummy prism 103 to be 0.5 mm or less, for example. For example, a
resolution of an observer whose eyesight is 0.5 is two minutes,
that is, 0.033.degree.. Accordingly, by setting a disposal pitch to
approximately 0.6 mm or less in a distance of 1 m, and a disposal
pitch to approximately 0.3 mm or less in a distance of 0.5 m,
patterns are discriminated by an observer. Accordingly, it is
preferable to set a disposal pitch to 0.5 mm or less, in a case in
which an observer views light guide plate display device 10 in a
distance of 1 m or more. When a distance between an observer and
light guide plate display device 10 is approximately 0.5 m, a
disposal pitch may be set to 0.3 mm or less.
[0075] Subsequently, a preferable configuration of light source
device 100 will be described with reference to FIGS. 17 and 18.
FIG. 17 is a sectional view which illustrates a part of light
source device 100 and light guide plate 101, and FIG. 18 is a
partial sectional view of light source device 100 and light guide
plate 101, and illustrates a section orthogonal to a thickness
direction of light guide plate 101 in FIG. 17. Light source device
100 includes light source 104, light source board 106, reflecting
plate 107, and light input lens 108.
[0076] Light sources 104 are, for example, light emitting diodes
(LED) which are arranged along end face 119 of light guide plate
101, and radiate light of colors of white, or blue, red, and green,
or a combination of these colors, conforming with a pattern
display. A size of the LED in a radiation face direction is
approximately 1 mm or more in general, in a case in which light
source 104 is LED, light source 104 is disposed at a disposal pitch
of at least 1 mm or more. On the other hand, a disposal pitch of
prism 102 and dummy prism 103 is set to approximately 0.5 mm or
less, in order to secure transparency of light guide plate 101.
Therefore, a disposal pitch of light source 104 is larger than
those of prism 102 and dummy prism 103. In FIG.17, light source 104
includes effective output face 112, and a length of effective
output face 112 in a thickness direction of light guide plate 101
is set to w1.
[0077] Light source board 106 includes light source mounting face
113, and mounts plurality of light sources 104 on light source
mounting face 113, in order to turn on plurality of light sources
104. Light source board 106 is a wiring board such as a glass epoxy
board, or a flexible board.
[0078] Reflecting plate 107 surrounds light source 104, light
source board 106, and light input lens 108 in a state in which a
portion between light source board 106 and end face 119 of light
guide plate 101 is opened. As a material of reflecting plate 107,
for example, there is a material obtained by performing mirror
finishing with respect to an aluminum plate, or a material obtained
by attaching a sheet deposited using silver or aluminum to a board
with high rigidity or a sheet.
[0079] Reflecting plate 107 is in close contact with light source
board 106, and radiates heat generated from light source 104 to the
outside. Reflecting plate 107 includes neck portion 105. Neck
portion 105 is located between light source mounting face 113 of
light source board 106 and effective output face 112 of light
source 104 when viewed planarly. Reflecting plate 107 passes
through effective output face 112 of light source 104 from neck
portion 105, and is open by being smoothly widened toward end face
119 of light guide plate 101. That is, an interval between
reflecting plates 107 of light guide plate 101 in the thickness
direction becomes extremely small in neck portion 105. In the
thickness direction of light guide plate 101, interval w2 between
reflecting plates 107 in neck portion 105 is set to be larger than
length w1 of effective output face 112 of light source 104. That
is, w1<w2.
[0080] Light input lens 108 is formed of a material different from
light guide plate 101, and is disposed between light source 104 and
end face 119 of light guide plate 101. Light input lens 108
includes first lens face 109 which faces light source 104. First
lens face 109 is configured of a plurality of cylindrical lenses,
and an axial direction of each cylinder is parallel in the
thickness direction of light guide plate 101. The cylindrical lens
of first lens face 109 and light source 104 are arranged at the
same disposal pitch 111. A focal point position of the cylindrical
lens of first lens face 109 is in the vicinity of effective output
face 112 of respective light sources 104.
[0081] Light input lens 108 includes second lens face 110 which
faces end face 119 of light guide plate 101. Second lens face 110
is configured of a plurality of cylindrical micro lens, and an
axial direction of each cylinder is parallel in the thickness
direction of light guide plate 101. A disposal pitch of a microlens
of second lens face 110 is smaller than disposal pitch 111 of first
lens face 109. A focal distance of the microlens of second lens
face 110 is shorter than the focal distance of the cylindrical lens
of first lens face 109. A pitch of the microlens is set to be a
non-integral multiple with respect to a disposal pitch of the
prism, in order to avoid moire. In FIG. 18, in second lens face
110, a convex-shaped microlens and a concaved microlens are
mutually arranged, and are configured as a smooth continuous face;
however, it is not limited to this, and second lens face 110 may be
configured by repeatedly disposing the convex-shaped microlens or
the concave-shaped microlens.
[0082] Subsequently, an operation of the above described light
source device 100 will be described with reference to FIGS. 19 to
21. In FIGS. 19 and 21, light beam 130 is radiated from light
source 104. In a section of light guide plate 101 in the thickness
direction, as illustrated in FIG. 19, light beam 130 radiated from
effective output face 112 of light source 104 passes through light
input lens 108 by being directly reflected, or is reflected on
reflecting plate 107, and is input to end face 119 of light guide
plate 101.
[0083] Neck portion 105 of reflecting plate 107 is located between
light source mounting face 113 of light source board 106 and
effective output face 112 of light source 104 when viewed planarly.
Therefore, all of light beams 130 which are radiated from effective
output face 112 of light source 104 proceed toward end face 119 of
light guide plate 101. Reflecting plate 107 opens toward end face
119 of light guide plate 101 by being smoothly widened. Therefore,
when light beam 130 is reflected on reflecting plate 107, light
beam 130 gets closer to rear face 120 of light guide plate 101 in
parallel. That is, the light beam becomes a slightly parallel
light. In this manner, the number of reflecting times of light beam
130 on reflecting plate 107 decreases, and it is possible to
suppress useless light absorbing on reflecting plate 107.
[0084] It is preferable for end face 119 of light guide plate 101
to be formed in a protruded V shape toward light source 104. By
setting end face 119 of light guide plate 101 to the V shape, an
input angle of light which passes thorough light guide plate 101
therein toward rear face 120 of light guide plate 101 becomes
slightly large. Therefore, it is not easy for the light to leak
from rear face 120 of light guide plate 101, and the light is
totally reflected on rear face 120 of light guide plate 101. In
this manner, the number of times of total reflection of light
increases, and the number of times of inputting to prism 102 also
increases. As a result, luminance in a pattern display of light
guide plate 101 improves.
[0085] An angle .phi. of the V shape of end face 119 of light guide
plate 101 may be set to approximately 166.degree.. In a case in
which .phi. is 160.degree. or less, light input from light source
device 100 to light guide plate 101 is not totally reflected inside
light guide plate 101, and most of components are leaked. When end
face 119 of light guide plate 101 is not formed in the V shape, and
is set to a protruded curved face toward light source 104, the same
effect is obtained.
[0086] First lens face 109 and second lens face 110 are cylindrical
lenses, and directions of cylindrical axes are parallel to the
thickness direction of light guide plate 101. Therefore, in a
section of light guide plate 101 in the thickness direction
illustrated in FIG. 19, there is no lens operation, and light beam
130 is input to end face 119 of light guide plate 101 by passing
thorough light input lens 108.
[0087] Light beam 131 which is input from light source device 100
to end face 119 of light guide plate 101, and is not output from
display face 121 of light guide plate 101 due to reflecting
inclined face .alpha. of prism 102 is input to light source device
100 which the light beam faces, as illustrated in FIG. 20. Light
beam 131 passes thorough light input lens 108, and is directly
input to light source board 106, or is input to thereto by being
reflected on reflecting plate 107.
[0088] Reflecting plate 107 includes neck portion 105 at a position
close to end face 119 of light guide plate 101, compared to light
source mounting face 113 of light source board 106. Therefore,
light beam 131 reflected on light source mounting face 113 is
reflected in neck portion 105, and is absorbed in light source
mounting face 113 by being input again.
[0089] Here, it is preferable that reflecting plate 107 be a
mirror-finished reflecting plate. In a case of assuming that
reflecting plate 107 is a diffuse reflecting plate, a component
which returns to the inside of light guide plate 101 by being
reflected in a diffusing manner on reflecting plate 107 is
generated from light beam 131 which passed through light input lens
108. Due to such a component which returns to the inside of light
guide plate 101, there is a concern that an unintended pattern may
be displayed on display face 121 of light guide plate 101. On the
other hand, in a case in which reflecting plate 107 is the
mirror-finished reflecting plate, since light beam 131 is reflected
so that an input angle and a reflecting angle become equal, the
light beam is absorbed in light source mounting face 113 of light
source board 106, finally. Therefore, the component which returns
to the inside of light guide plate 101 is not generated, and it is
possible to prevent an unintended pattern from being displayed on
display face 121 of light guide plate 101.
[0090] It is preferable that light source mounting face 113 of
light source board 106 be coated with a black color, or the like,
so as to increase light absorptivity. That is, it is preferable
that light source mounting face 113 of light source board 106 be a
black color. In a case in which the light absorptivity of light
source mounting face 113 of light source board 106 is low, there is
a concern that light beam 131 which reaches light source mounting
face 113 of light source board 106 is reflected on light source
mounting face 113, passes thorough light input lens 108 again, and
returns to the inside of light guide plate 101. By increasing the
light absorptivity of light source mounting face 113 of light
source board 106, it is possible to suppress returning of light
beam 131 to the inside of light guide plate 101 by being reflected
on light source mounting face 113.
[0091] On the other hand, as illustrated in FIG. 21, light beam 130
which radially expands from effective output face 112 of light
source 104 is input to first lens face 109 of light input lens 108,
when viewed in the thickness direction of light guide plate 101.
First lens face 109 is configured of a cylindrical lens of which an
axis is parallel to the thickness direction of light guide plate
101, and a focal position thereof is in the vicinity of effective
output face 112 of light source 104. Therefore, light beam 130
becomes a parallel light by passing thorough first lens face
109.
[0092] Light beam 130 which is input to first lens face 109 of
light input lens 108 is output from second lens face 110. Second
lens face 110 is configured of cylindrical microlens of which an
axis is parallel to the thickness direction of light guide plate
101. Therefore, light beam 130 which becomes parallel light due to
first lens face 109 is diffused by passing thorough second lens
face 110. Since a plurality of microlenses on second lens face 110
are provided with respect to one light source 104, light output
from light input lens 108 become the number of light sources
corresponding to microlenses of second lens face 110, ostensibly.
By setting a pitch of the microlenses to be sufficiently narrow,
light source device 100 is regarded as a line-shaped light source
which is continuous in a direction parallel to end face 119 of
light guide plate 101.
[0093] When assuming a case in which light input lens 108 is not
provided in light source device 100, reflecting inclined face
.alpha. of prism 102 takes a role of a mirror. Therefore, when an
observer views display face 121 of light guide plate 101, effective
output face 112 of light source 104 is viewed, and only part of
luminance increases or decreases, as a result, a bright line
occurs. In contrast to this, by setting light source device 100 to
a line-shaped light source, it is possible to input light to end
face 119 of light guide plate 101 uniformly, and make luminance be
balanced, by remarkably decreasing the bright line.
[0094] As described above, it is preferable that light source
device 100 include light input lens 108; however, as illustrated in
FIG. 22, it may be a configuration in which light source device 100
does not include light input lens 108, and instead, end face 119 of
light guide plate 101 is formed in a shape in which a plurality of
cylindrical lenses and a plurality of microlenses are overlapped.
In other words, end face 119 of light guide plate 101 is configured
of a plurality of microlenses, and the microlens is formed in a
cylindrical shape in which an envelope curve of the microlenses is
set to a focal point in the vicinity of effective output face 112
of light source 104. Hereinafter, descriptions will be made in
detail.
[0095] Light input lens 108 takes a role of making output light
which radially expands from light source 104 parallel in the
cylindrical lens on first lens face 109, and causing the paralleled
light to be diffused in the microlens on the second lens face 110.
In this manner, output light is refracted on two faces of first
lens face 109 and second lens face 110 in total, and it is possible
to reduce the bright line from light source 104.
[0096] On the other hand, as illustrated in FIG. 22, in a case in
which end face 119 of light guide plate 101 is configured,
parallelizing and diffusing of output light are performed at the
same time, on end face 119 of light guide plate 101, that is, on
one face. Therefore, in this case, it is possible to reduce the
bright line, compared to a case in which there is no cylindrical
lens and microlens. It is possible to obtain a remarkable
refraction operation by using many faces due to the refraction
operation of light. Therefore, an effect of reducing the bright
line decreases in a case of refracting output light on one face, as
described above, compared to the case in which output light is
refracted on two faces using light input lens 108. However, since
light input lens 108 is not used, it is possible to reduce a
manufacturing cost by reducing constituent members.
[0097] In the above descriptions, as illustrated in FIG. 3, angle
.theta..sub..beta. formed by rear face 120 of light guide plate 101
and transmitting inclined face .beta. of prism 102 is set to
approximately 90.degree.. However, for example, in order to attach
a draft angle when separating light guide plate 101 from a mold at
a time of machining light guide plate 101, .theta..sub..beta. is
set to be smaller than 90.degree., and for example, may be set to
70.degree. to 89.degree.. Since a ratio of a light beam which
penetrates transmitting inclined face .beta. without being
reflected becomes high when .theta..sub..beta. is close to
90.degree., it is preferable to set .theta..sub..beta. to
approximately 90.degree.. When .theta..sub..beta. is smaller than
70.degree., a ratio of light beam output to display face 121 of
light guide plate 101 by being reflected on transmitting inclined
face .beta. increases, and there is a concern that an unintended
pattern may be displayed.
[0098] The case in which LED is adopted as light source 104 is
described; however, a line-type light source such as an
electroluminescence, a fluorescent tube, or the like, may be used.
The case in which light guide plate 101 is a flat-plate shape is
described; however, it may be a slightly curved shape.
[0099] In FIGS. 5 to 9, patterns A to D are formed in different
shapes; however, it is also possible to display a plurality of
colors by setting the patterns to the same shape, and colors of
light source device 100 to red, blue, and green.
[0100] It is also possible to perform highlighting such as a
blinking display, and a display using a change in color, or a
simple movie display, by changing an output of a plurality of light
source devices 100, by causing the output to be changed by being
synchronized in time. In the pattern display, an edge of a pattern
is emphasized by setting a height of prism 102 at an edge portion
of a pattern to be higher than that of prism 102 at a portion other
than the edge portion, and it is possible to perform a pattern
display which is easy to view.
[0101] The number of display patterns is not limited to four types.
The number of sides of prism 102 and dummy prism 103 is, for
example, set to three in a case of a pattern display of three
types, set to five, in a case of a pattern display of five types,
as illustrated in FIG. 23, and set to m in a case of a pattern
display of m types. At this time, side faces of prism 102 have at
least inclines of two stages of reflecting inclined face .alpha.
and transmitting inclined face .beta., respectively, and it is
possible to perform a pattern display of arbitrary types, similarly
to the case of a pattern display of four types, by setting an area
of reflecting inclined face .alpha..
[0102] A shape of light guide plate 101 is not limited to a regular
polygon. For example, as illustrated in FIG. 23, the light guide
plate is a scalene shape, light source device 100 is disposed in
each side, and a shape of prism 102 and dummy prism 103 may be set
according to the shape of light guide plate 101.
[0103] As illustrated in FIG. 24, light input lens 118 in which a
total reflection face is provided on first lens face 109 may be
used, instead of light input lens 108. By providing the total
reflection face on first lens face 109, it is possible to make
light radiated from light source 104 be parallel, by capturing much
more light on first lens face 109, and luminance of pattern display
improves. It may be a configuration in which both of light input
lens 108 and light input lens 118 are not used, and end face 119 of
light guide plate 101 is formed in a shape in which a cylindrical
lens in which a total reflection face is provided and a microlens
are overlapped with each other.
[0104] Light source device 100 is set to a line shape by combining
light source 104 such as LED and light input lens 108; however, it
may be set to a line shape using a light guiding rod system. In
this case, light of light source 104 is input from an end face of
the light guiding rod, the light is extracted from the light
guiding rod using a prism formed on a side face of the rod, and
light in a uniform line shape is obtained.
[0105] The number of side faces of prism 102 and dummy prism 103 is
set to the same number as that of light source device 100; however,
the number of side faces of the prism may be set to be larger than
that of light source device 100. In this case, a side face which
does not face light source device 100 is configured, using only
transmitting inclined face .beta. for non-display. For example, a
case in which a display pattern which is displayed by using three
light source devices 100, and a display pattern which is displayed
by using four light source devices 100 are disposed on one light
guide plate 101 will be assumed. In this case, prism 102 with three
side faces, and prism 102 with four side faces may be respectively
disposed. However, when such prisms 102 of two types are mixed,
mold machining is apt to be complicated. Therefore, in a pattern
displayed by using three light source devices 100, one inclined
face of a prism with four side faces is set to transmitting
inclined face .beta. for non-display, by setting the number of side
faces of the prism to be larger than the number of light source
devices 100. By doing so, it is possible to perform a unification
of a prism with four side faces, and machining of a mold becomes
easy.
[0106] Light may not necessarily be radiated from all of light
source devices 100 to prism 102 and dummy prism 103. That is, a
shape of light guide plate 101 and light source device 100 may be
disposed so that the number of light source devices 100 which is
radiated to a region is changed in each of the regions of light
guide plate 101. Prism 102 of which the number of side faces is
changed in each region may be disposed.
INDUSTRIAL APPLICABILITY
[0107] The light guide plate display device in the present
invention has high transparency, and can display a plurality of
patterns. Therefore, the display device can be used in amusements,
an accessory light for illumination, or the like.
REFERENCE MARKS IN THE DRAWINGS
[0108] 100, 100a, 100b, 100c, 100d light source device
[0109] 101 light guide plate
[0110] 102 prism
[0111] 102A side face
[0112] 103 dummy prism
[0113] 104 light source
[0114] 105 neck portion
[0115] 106 light source board
[0116] 107 reflecting plate
[0117] 108, 118 light input lens
[0118] 109 first lens face
[0119] 110 second lens face
[0120] 111 disposal pitch
[0121] 112 effective output face
[0122] 113 light source mounting face
[0123] 119 end face
[0124] 120 rear face
[0125] 121 display face
[0126] 130, 131, 133, 134, 135, 136, 137, 138 light beam
[0127] 140 reflecting position
[0128] .alpha. reflecting inclined face
[0129] .beta. transmitting inclined face
[0130] .gamma. planar face
* * * * *